Large-scale integration of atomically thin metals (e.g., graphene), semiconductors (e.g., transition metal dichalcogenides (TMDs)), and insulators (e.g., hexagonal boron nitride) is critical for constructing the building blocks for future nanoelectronics and nanophotonics, as described in Roy, K., et al., “Graphene-MoS2 hybrid structures for multifunctional photoresponsive memory devices,”8 Nat. Nanotechnol. 826-830 (2013); Yu, W. J., et al., “Vertically stacked multi-heterostructures of layered materials for logic transistors and complementary inverters,” 12 Nat. Mater. 246-252 (2012); Dean, C. R., et al., “Boron nitride substrates for high-quality graphene electronics,” 5 Nat. Nanotechnol. 722-726 (2010); Liu, Z., et al., “In-plane heterostructures of graphene and hexagonal boron nitride with controlled domain sizes,” 8 Nat. Nanotechnol. 119-124 (2013); Yu, W. J., et al., “Highly efficient gate-tunable photocurrent generation in vertical heterostructures of layered materials,” 8 Nat. Nanotechnol. 952-958 (2013); and Britnell, L., et al., “Strong light-matter interactions in heterostructures of atomically thin films,” 340 Science 1311-1314 (2013). However, the construction of in-plane heterostructures, especially between two atomic layers with large lattice mismatch, can be extremely difficult due to the strict requirement of spatial precision and the absence of a selective etching method.
As the fundamental limit of Moore's law is approaching, the global semiconductor industry is intensively looking for applications beyond complementary metal-oxide-semiconductor (CMOS) electronics. The atomically thin and ultra-flexible nature of two-dimensional (2D) materials [such as graphene, hexagonal boron nitride (hBN) and transition metal dichalcogenides (TMDs)] offer a competitive solution not only to push the forefront of semiconductor technology further, towards or perhaps beyond Moore's law, but also to potentially realize a vision of ubiquitous electronics and optoelectronics in the near future. Hybrid structures between 2D materials are essential building blocks with multi-functionality and broader capacity for nanoscale modern electronics and optoelectronics. The stacking of van der Waals heterostructures in the vertical direction can be accomplished by either mechanical transfer or hetero-epitaxy, whereas atomic stitching of 2D materials in the horizontal direction through conventional nanofabrication technology has proven to be far more challenging, mainly because of the lack of a selective etching method for each specific 2D material. Precise spatial control and self-limiting processes are highly desired to design and prepare lateral heterostructures. Researchers have attempted to build lateral heterostructures between materials with similar lattice structures and small lattice mismatch, such as graphene-hBN, and TMD-TMD lateral heterostructures. However, parallel connection between two atomically layers with significant crystallographic dissimilarity, such as graphene-TMD or hBN-TMD lateral heterostructures, has never been achieved. Furthermore, most of these methods are not suitable for large-scale production.